The increase in the fraction of high-valent metal cations is of significant importance for enhancing the stability of noble-metal-free catalysts in the acid oxygen evolution reaction (OER). Herein, we report the preparation of a cobalt-manganese oxide spinel nanowire catalyst, where the incorporation and stabilization of high-valent cation fractions are induced by electron-withdrawing anionic fluorine groups. By the XPS, the strongly electronegative F atoms improve the ratio of Co3+/Co2+ and Mn4+/Mn3+, thereby enhancing OER activity and stability. The hydrophilicity F-MCO nanowires have a large specific surface area and great conductivity, which expose more catalytically active sites and continuously promotes oxygen evolution. The proposed F-MCO catalyst requires only an overpotential of 210 mV at the current density of 10 mA cm−2 and can maintain stable operation for more than 100 h. And a photovoltaic-electrolysis device with the F-MCO electrocatalyst delivers a solar-to-hydrogen efficiency of 15.1 %.